package com.bluesimon.wbf.view;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

/**
 * 验证码
 */
@RestController
public class VerificationCodeController {

    /**
     * 这里用作存入session的名称
     */
    public static final String SESSION_KEY_OF_RAND_CODE = "randCode"; // todo 要统一常量

    /**
     * 
     */
    private static final int count = 200;

    /**
     * 定义图形大小(宽)
     */
    private static final int width = 95;

    /**
     * 定义图形大小(高)
     */
    private static final int height = 30;

    /**
     * 干扰线的长度=1.414*lineWidth
     */
    private static final int lineWidth = 1;

    /**
     * 生成验证码
     */
    @RequestMapping(value = "/v0.1/verificationcode/generate", method = { RequestMethod.POST, RequestMethod.GET })
    public void VerificationCode(HttpServletRequest request, HttpServletResponse response) throws ServletException,
            IOException {
        // 设置页面不缓存
        response.setHeader("Pragma", "No-cache");
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expires", 0);
        // response.setContentType("image/png");
        // 在内存中创建图象
        final BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        // 获取图形上下文
        final Graphics2D graphics = (Graphics2D) image.getGraphics();

        // 设定背景颜色
        graphics.setColor(new Color(83,195,239)); // ---1.Color.WHITE为白色
        //graphics.setColor(Color.TRANSLUCENT); // ---1.Color.WHITE为白色
        graphics.fillRect(0, 0, width, height);// 填充衍射
        // 设定边框颜色
        // graphics.setColor(getRandColor(100, 200)); //
        // ---2.这是以数字型来设置颜色，颜色模式是指使用三种基色：红、绿、蓝，通过三种颜色的调整得出其它各种颜色，这三种基色的值范围为0～255
        graphics.drawRect(0, 0, width - 1, height - 1);

        final Random random = new Random();
        // 随机产生干扰线，使图象中的认证码不易被其它程序探测到
        for (int i = 0; i < count; i++) {
            //graphics.setColor(getRandColor(150, 200)); // ---3.

            graphics.setColor(Color.WHITE); // ---3.
            final int x = random.nextInt(width - lineWidth - 1) + 1; // 保证画在边框之内
            final int y = random.nextInt(height - lineWidth - 1) + 1;
            final int xl = random.nextInt(lineWidth);
            final int yl = random.nextInt(lineWidth);
            graphics.drawLine(x, y, x + xl, y + yl);
        }
        // 取随机产生的认证码(4位数字)
        final String resultCode = exctractRandCode();
        for (int i = 0; i < resultCode.length(); i++) {
            // 将认证码显示到图象中,调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
            // graphics.setColor(new Color(20 + random.nextInt(130), 20 + random
            // .nextInt(130), 20 + random.nextInt(130)));

            // 设置字体颜色
            //graphics.setColor(Color.BLACK);
            graphics.setColor(Color.WHITE);
            // 设置字体样式
            // graphics.setFont(new Font("Arial Black", Font.ITALIC, 18));
            graphics.setFont(new Font("Times New Roman", Font.BOLD, 24));
            // 设置字符，字符间距，上边距
            System.out.print(resultCode.charAt(i));
            graphics.drawString(String.valueOf(resultCode.charAt(i)), (23 * i) + 8, 26);
        }
        System.out.println("直接输出：" + resultCode);
        // 将认证码存入SESSION
        request.getSession().setAttribute(SESSION_KEY_OF_RAND_CODE, resultCode);
        // 图象生效
        graphics.dispose();

        // 输出图象到页面
        ImageIO.write(image, "JPEG", response.getOutputStream());
    }
    
    /**
     * @return 随机码
     */
    private String exctractRandCode() {
        final String randCodeType = "6";
        int randCodeLength = Integer.parseInt("4");
        switch (randCodeType.charAt(0)) {
        case '1':
            return RandCodeImageEnum.NUMBER_CHAR.generateStr(randCodeLength);
        case '2':
            return RandCodeImageEnum.LOWER_CHAR.generateStr(randCodeLength);
        case '3':
            return RandCodeImageEnum.UPPER_CHAR.generateStr(randCodeLength);
        case '4':
            return RandCodeImageEnum.LETTER_CHAR.generateStr(randCodeLength);
        case '5':
            return RandCodeImageEnum.ALL_CHAR.generateStr(randCodeLength);
        case '6':
            return RandCodeImageEnum.UPPER_NUMBER_CHAR.generateStr(randCodeLength);            
        default:
            return RandCodeImageEnum.NUMBER_CHAR.generateStr(randCodeLength);
        }
    }

    /**
     * 描述：根据给定的数字生成不同的颜色
     * @param 这是以数字型来设置颜色，颜色模式是指使用三种基色：红、绿、蓝，通过三种颜色的调整得出其它各种颜色，这三种基色的值范围为0～255
     * @param 这是以数字型来设置颜色，颜色模式是指使用三种基色：红、绿、蓝，通过三种颜色的调整得出其它各种颜色，这三种基色的值范围为0～255
     * @return 描述：返回颜色
     */
    private Color getRandColor(int fc, int bc) { // 取得给定范围随机颜色
        final Random random = new Random();
        if (fc > 255) {
            fc = 255;
        }
        if (bc > 255) {
            bc = 255;
        }

        final int r = fc + random.nextInt(bc - fc);
        final int g = fc + random.nextInt(bc - fc);
        final int b = fc + random.nextInt(bc - fc);

        return new Color(r, g, b);
    }

    /**
     * 验证码辅助类
     */
    enum RandCodeImageEnum {
        /**
         * 混合字符串
         */
        ALL_CHAR("0123456789abcdefghijkmnpqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"), // 去除小写的l和o这个两个不容易区分的字符；
        /**
         * 字符
         */
        LETTER_CHAR("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"),
        /**
         * 小写字母
         */
        LOWER_CHAR("abcdefghijklmnopqrstuvwxyz"),
        /**
         * 数字
         */
        NUMBER_CHAR("0123456789"),
        /**
         * 大写字符
         */
        UPPER_CHAR("ABCDEFGHIJKLMNOPQRSTUVWXYZ"),
        
        /**
         * 大写字符+數字
         */
        UPPER_NUMBER_CHAR("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ");
        /**
         * 待生成的字符串
         */
        private String charStr;

        /**
         * @param charStr
         */
        private RandCodeImageEnum(final String charStr) {
            this.charStr = charStr;
        }

        /**
         * 生产随机验证码
         * 
         * @param codeLength
         *            验证码的长度
         * @return 验证码
         */
        public String generateStr(final int codeLength) {
            final StringBuffer sb = new StringBuffer();
            final Random random = new Random();
            final String sourseStr = getCharStr();

            for (int i = 0; i < codeLength; i++) {
                sb.append(sourseStr.charAt(random.nextInt(sourseStr.length())));
            }

            return sb.toString();
        }

        /**
         * @return the {@link #charStr}
         */
        public String getCharStr() {
            return charStr;
        }
    }
}
